The more all-mountain/freestyle-centric boards in the K2 line are:
Darkstar - my friend has this (08/09 model), it handles everything pretty damn well.
Jibpan - I own the 07/08 model. It's softer than the Darkstar, has great damping (07/08 has the pre-patent form of Harshmellow) but it already wasn't very good in pow, and the 08/09 on paper should be even worse in pow due to its Jib Tips.
Believer - never ridden it; no comment.
As for more boards like the Weapon, jmac's got em down. I'll just add the Signal Park Series/Rocker to that list.